QR hub: diameter of hollow hub axle
#1
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QR hub: diameter of hollow hub axle
The skewer of a QR has a diameter of 5mm.
What is the diameter of the hollow hub axle (skewer is inserted into this)? Is this diameter a standard?
Thanks
What is the diameter of the hollow hub axle (skewer is inserted into this)? Is this diameter a standard?
Thanks
#2
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The ID of a qr hub is nominally 5mm and allows passage of the skewer. Pretty much all qr hubs are the same.
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I don't think there is a "standard". However since the outer diameter of the axle is somewhat controlled by the slot in the fork ends or drop outs and the skewer has to have room to be installed and removed, that over the many many years skewers have been with us that most holes through axles requiring a skewer will be pretty close to the same. I doubt any manufacturer wanted to risk making a product that wouldn't work with others for this particular application and time period. Might see some differences because of the grade of steel or other material that is used for the axle. But not so much that one skewer won't work with another.
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the shaft of many (most) titanium skewer quick releases measure close to 4mm
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My steel skewers are all 4.5mm in diameter, and the nuts that go on the threaded end are all interchangeable. The bore (inner axle diameter) is 5mm. The conical springs keep the skewer centered.
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#7
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A quick release wheel has a hollow axle, 9mm in diameter at the front and 10mm at the rear, with a 5mm diameter skewer that passes through it.
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"Stensile (sic) strength measures the maximum stress that a structure can sustain. Stainless steel’s tensile strength is 485 MPa versus titanium’s 480 MPa. For some additional perspective, aluminum has an MPa of only 90 and copper’s MPa is only 200."
SOURCE
That's about a 1% decrease in tensile strength.
EDIT: I found a value closer to the one you quoted HERE in Table 1. I can't explain the discrepancy, but I *can* verify that my titanium skewers have held up for over 20 years. I'm not a metallurgist!
Last edited by sweeks; 07-04-22 at 08:48 PM.
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The shaft is typically about 4.5mm diameter, but the threaded section is created by rolling the threads rather than cutting them, so the diameter of the threaded section ends up 5mm diameter.
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If the question is what is the axle's through hole, that positions the QR skewer, than I would speculate it's slightly bigger than 5mm to allow for a bit of clearance. I also suspect that different axle manufacturers will have their axle "holes" a tad different but all close to the same dimension. Of course one could measure and then we would not have to wonder which aspect was in question, or what the dimension actually is. Andy
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#13
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EDIT: I found a value closer to the one you quoted HERE in Table 1. I can't explain the discrepancy, but I *can* verify that my titanium skewers have held up for over 20 years. I'm not a metallurgist!
Anyway, thanks for that link.
I think the difference must be stainless steel vs. more "normal" alloys of steel. I also discovered one pair of my skewers is indeed Ti.
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There may have been rare exceptions to the use of standard-diameter skewers (and thus hub axle I.D.s). I have a vague memory of Weyless hubs using proprietary dimensions for their hubs. Maybe larger-diameter aluminum skewers. Could easily be wrong, though.
#15
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If the question is what is the axle's through hole, that positions the QR skewer, than I would speculate it's slightly bigger than 5mm to allow for a bit of clearance. I also suspect that different axle manufacturers will have their axle "holes" a tad different but all close to the same dimension. Of course one could measure and then we would not have to wonder which aspect was in question, or what the dimension actually is. Andy
Is it possible that 9mm and 10mm are the outer diameters of the hollow tube that is the axle's through hole?
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You can have Strong, Light,or Cheap: Pick Two. Lightness generally comes at the expense of Strength.
Nobody is making you put Ti skewers on your LHT.
(Also, if your QR skewer is a weight- bearing element; you're doing something wrong)
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A Ti fastener will always be weaker than the same fastener in steel, but significantly lighter.
You can have Strong, Light,or Cheap: Pick Two. Lightness generally comes at the expense of Strength.
Nobody is making you put Ti skewers on your LHT.
(Also, if your QR skewer is a weight- bearing element; you're doing something wrong)
You can have Strong, Light,or Cheap: Pick Two. Lightness generally comes at the expense of Strength.
Nobody is making you put Ti skewers on your LHT.
(Also, if your QR skewer is a weight- bearing element; you're doing something wrong)
The usual mode of failure is for the threads to strip out the nut, or to strip off. (I suppose they can also break the spindle from over-stretching while over-tightening, but titanium is actually more able to withstand that than is steel.)
This is probably most important for folks who have disc brakes and quick-release (rather than thru-axle). Because of the downward force during braking, the wheel has a tendency to move within the dropouts of the fork, or will even have a tendency to be ejected from the fork if the dropouts aren't forward-facing. This encourages the user to crank down on them as much as possible. Before I got internal cam Dura Ace and DT Swiss skewers, my front wheel would need to be re-seated after hard braking or I would get a bit of pad rub on the disc. If you are going to crank it down hard, you will want strength.
Thru axles weigh a lot more than quick release skewers and their end-caps, and I have never heard anyone complain about their weight.
Last edited by Polaris OBark; 07-06-22 at 11:45 AM.
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One of those transition technologies from the end of the 26'er era.
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The outer diameter of the axles on my wheels are either 15mm (6802 or 6902 bearings) or 17 mm (6803 or 6903 bearings).
My old crap with loose balls is 10 mm IIRC
My old crap with loose balls is 10 mm IIRC
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Ti is too finicky, IMHO, for field repairs on something as basic as a bicycle.
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I didn't realize the external cam QR skewers I replaced with internal cam steel skewers (and later, DT Swiss steel skewers) were titanium until a couple of days ago. I had just assumed that the problem was that they were external cams, but it might be the titanium was stretching under load a wee bit.
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I didn't realize the external cam QR skewers I replaced with internal cam steel skewers (and later, DT Swiss steel skewers) were titanium until a couple of days ago. I had just assumed that the problem was that they were external cams, but it might be the titanium was stretching under load a wee bit.
So, for me - no discs and simple, reliable, all steel (aluminum levers and heads are OK) internal cam QRs of modern design (the new cam shape, not the old Campy NR shape with it's far less secure locking). Good thing is such levers are easy to find. Lesser modern all steel Campy QRs are sweet. So is my Ultegra of the 9-speed era. I have a really cheap modern Shimano that looks its price range with really good action; as good as anything I've used.
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As the OP topic has been answered by a few here I would not be bothered by continuing blabbing. Andy (who questions the claim of older Campy NR skewers being of poor clamping force)
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